What Are the Symptoms of a Nut Allergy in Kids?

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Your seven-month-old has just broken out in hives. You’ve been gradually introducing solids, but haven’t introduced anything new in a few days. Still, you ate a messy peanut butter sandwich before feeding your baby and are wondering if your baby accidentally ingested a bit of the peanut butter. Even with the hives, your baby seems fine, but peanut allergies run in your family and you’re worried.

Your two-year-old hasn’t had any allergic food reactions to date, but just grabbed a brownie with walnuts from a playmate, and has come to you crying, saying their mouth feels “itchy.” You’re not sure if your child has ever eaten a walnut before, and now you’re worried they might be having an allergic reaction.

Many of us parents have been there, too—wondering if our child’s symptoms may indicate an allergic reaction. Reactions to nuts are especially scary because we’ve all heard stories of kids having serious and even fatal allergic reactions to nuts.

We connected with a pediatrician and two allergists to help parents understand what to look for when it comes to nut allergy symptoms in children—and what you should do if your child is showing any signs of an allergic reaction.

Overview of Nuts and Nut Allergies

It’s important to understand that “nuts” is a broad term, and there are actually two different categories of nuts that a child could be allergic to. The first category is peanuts (which are actually legumes). The second category is tree nuts, which include: almonds, cashews, walnuts, hazelnuts, macadamia nuts, Brazil nuts, pistachios, and cashews.

Both peanut allergies and tree nut allergies are among the eight most common allergenic foods. About 5% of children in America have food allergies, and both peanuts and tree nuts—along with fish and shellfish—are the allergens most likely to cause the most severe allergic reactions.

Peanut allergies in particular are prevalent. As the American College Of Allergy, Asthma, and Immunology notes, about 2.5% of children have an allergy to peanuts, and that number has increased 20% since 2010. Although peanut allergies and tree nut allergies are different types of allergies, they are related: between 25-40% of people who are allergic to peanuts are also allergic to tree nuts.

Which Nuts Cause the Most Allergic Reactions?

According to Dr. Stephanie Leeds, a pediatric allergist at Yale New Haven Children’s Hospital, peanuts cause the most allergic reactions in children. Any tree nut can cause an allergic reaction, she explains, but certain tree nuts are more likely to, including cashews and walnuts.

How Long After Eating Nuts Will a Child’s Allergic Reaction Occur?

When most of us think of allergies, we think of an immediate reaction to the allergen. But while many allergic reactions happen suddenly, some come on a bit more gradually. “Typically, a conventional food allergic reaction happens within minutes to two hours after exposure,” Dr. Leeds explains.

The timing of your child’s allergic reaction often corresponds with how serious the reaction is, explains Dr. Tiffany J. Owens, an allergist and immunologist at The Ohio State University Wexner Medical Center and assistant professor at The Ohio State University College of Medicine.

“The most concerning reactions are those that occur nearly immediately, as in within a few minutes up to one hour,” she says. The longer it takes for your child to show symptoms of a nut allergy, the less likely it is that your child is experiencing a nut allergy, Dr. Owens adds.

Symptoms of Nut Allergies

The symptoms of nut allergies vary from child to child and can depend on what type of nut they are allergic to and how severe their allergy to the nut is. Even a very small amount of allergen can cause symptoms; according to Johns Hopkins Medicine, 1/44,000 of a peanut kernel can cause a reaction in an allergic individual.

Nut allergy symptoms happen because of an overreaction in a child’s immune system. The child’s body sees the nut protein as an invader and releases large amounts of histamine to fight the perceived threat. Excessive amounts of histamine are what cause the tell-tale symptoms of food allergies.

What Are the Most Common Symptoms?

There is a wide range of symptoms when it comes to nut allergies in kids, from mild, to moderate, to severe. Reactions often vary depending on the age of your child.

Dr. Wendy Sue Swanson, pediatrician and chief medical officer at SpoonfulONE, says that the most common signs of a nut allergy in infants and toddlers are hives and/or vomiting. Older children are likely to have more numerous symptoms, such as swelling, wheezing, difficulty breathing, and anaphylaxis (a severe and sometimes fatal allergic reaction).

Other common symptoms of nut allergies include itching, runny nose, coughing, and sneezing, says Dr. Leeds. Eyelid swelling, diarrhea, and dizziness may also be present, Dr. Owens shares.

Any sign of anaphylaxis—which can include difficulty breathing, dizziness, extreme drops in blood pressure, and shock—requires emergency medical attention.

What Symptoms Might Be Harder to Detect?

Most of us are familiar with the most common signs of nut allergies. But at times, the signs of a nut allergy might be more subtle.

“Stomach aches or sleepiness in children who are not yet able to speak or describe their symptoms may be overlooked,” says Dr. Owens. Dr. Leeds explains that some less obvious signs of allergic reactions may include feelings of confusion, or an “impending sense of doom.”

Nut Allergy Reactions

In addition to the more subtle signs of allergic reactions, it can be helpful to understand the difference between a mild and more severe allergic reaction.

What Might Milder Reactions Look Like?

A more mild allergic reaction to nuts may look like an itchy or runny nose, an itchy mouth, sneezing, and mild tummy pain, says Dr. Leeds. Your child may be showing signs of a milder allergic reaction when they have a few “scattered hives,” explains Dr. Owens. Or they may have swelling of just one side of their lip.

What Might an Emergency Allergic Reaction to Nuts Look Like?

Although all allergic reactions should be taken seriously, if your child is showing signs of a severe allergic reaction, this is considered a medical emergency. Call 911 immediately; if you have emergency allergy medication, such as an EpiPen, you should administer that right away.

Signs of severe allergic reactions include “full-body hives and swelling, trouble breathing or swallowing, feeling faint or passing out, and repetitive vomiting,” says Dr. Leeds. The most severe allergic reactions to nuts happen quickly after exposure, Dr. Owens notes, and may include swelling of the eyelid or lip, coughing, drooping, itching, hives, and vomiting.

Again, if your child is having symptoms of a severe allergic reaction, you should not hesitate to administer your emergency medication and call emergency services. Go with your instincts; it’s always better to be safe than sorry when it comes to severe allergic reactions.

Addressing Nut Allergies

If you suspect that your child may have a nut allergy, you should visit your pediatrician or an allergist. If you visit your pediatrician first, and they suspect that your child may have a nut allergy, they will likely refer you to a pediatric allergist.

“If there is any concern for potential reactions to peanut or tree nut, you should see a board certified allergist, hopefully one who has experience with the nuances of working up food allergy,” Dr. Leeds shares.

Testing for Nut Allergies

After your allergist takes a detailed history of your child’s allergic experiences, including prior exposures and possible reactions, your allergist will likely run some tests to further understand your child’s allergies, says Dr. Leeds. This will include blood tests and skin prick tests. "[In all cases], it is incredibly important that a detailed history precedes any testing because allergy tests can often have ‘false positives.’”

Dr. Swanson explains that blood tests measure your child’s immune response to foods that you suspect they may be allergic to, and check the amount of immunoglobulin E (IgE) antibodies in their blood.

A skin test is administered by exposing your child's skin to a small amount of the allergen, pricking their skin with a needle, and then looking for reactions, such as raised bumps. Other possibilities include “oral food challenges,” where small, safe amounts of the allergen are fed to your child in the allergist’s office and your child is monitored for reactions.

Treating Nut Allergies

Treating your child’s nut allergies involves avoiding all ingestions of the nut your child is allergic to. This is not as easy as it may sound, since peanut and tree nut ingredients are added to pre-packaged ingredients, baking mixes, and sauces. This means that you will become a very careful label reader if your child develops a nut allergy.

Cross-contamination is also possible, so watch for warnings such as “product was manufactured on equipment shared with tree nuts or peanuts.”

Additionally, you will always want to have medication on hand to treat any possible exposure to the allergen, because they can happen even if you are being extremely careful. “For isolated mild symptoms, we recommend using an antihistamine, like Benadryl for treatment,” says Dr. Leeds. Severe symptoms require the immediate administration of an epinephrine auto-injector, like an EpiPen.

You will also want to take care to have a thorough and open discussion with your doctor about your child’s individual treatment plan. This will help you maximize your success as an allergy parent. “Every child should have an individualized assessment and treatment plan, and these providers can counsel directly on food avoidance strategies, reading labels, and treatment options,” Dr. Leeds shares.

UPDATE: January 2023

As of January 1, 2023, labels on food products must list sesame as an allergen. This is a new requirement from the Food and Drug Administration (FDA). But if you are allergic to sesame, you should still be cautious of the foods you are buying. The law doesn't require products on their way to stores or already on shelves by January 1st to list sesame on the label. Those foods also don't need to be removed or relabeled. Sesame joins eight other food allergens that already must be listed on labels: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans.

Preventing Nut Allergies

If nut allergies run in your family, or if you are concerned about your child developing a nut allergy, you may be wondering what you can do to prevent this from happening. While there is no surefire way of preventing food allergies (sometimes they just happen!), there is some evidence that introducing your baby to allergens early in life can help.

New feeding guidelines from both the Academy of American Pediatrics (AAP) and the USDA recommend introducing your child to common allergens as early as 4-6 months, says Dr. Swanson. “Early and routine introduction of ALL common allergens around 4-6 months of age is critical to reducing risk,” Dr. Swanson explains.

Both the AAP and USDA state that introducing nuts in the 4-6 month range is most important for children at high risk of developing nut allergies, such as children with a family history of allergies. Any decision about how and when to introduce allergens to your child should be made in collaboration with your pediatrician.

A Word from Verywell

If your child suddenly shows allergy symptoms soon after eating a peanut or tree nut, it’s understandable that you will feel worried, and maybe even panicky. Allergies are frightening, and no one wants to see their child feeling or looking unwell. If your child is exhibiting symptoms that might indicate an allergic reaction, try not to panic, but also make sure to take the symptoms seriously.

If the symptoms appear mild, call your pediatrician’s office for advice or to make an appointment for further examination. If your child is showing any signs of a severe reaction—trouble breathing, full body hives or swelling, extreme lethargy, vomiting, or signs of shock—do not hesitate to call 911 or drive your child to the nearest emergency room.

6 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Johns Hopkins All Children’s Hospital website. Nut and Peanut Allergy.

  2. Johns Hopkins All Children’s Hospital website. Food Allergies in Children.

  3. American College of Allergy, Asthma, and Immunology website. Peanut Allergy.

  4. American College of Allergy, Asthma, and Immunology website. Tree Nut Allergy.

  5. Johns Hopkins Medicine. Food Allergies in Children.

  6. Food and Drug Administration (FDA). Allergic to Sesame? Food Labels Now Must List Sesame as an Allergen.

Additional Reading

By Wendy Wisner
Wendy Wisner is a lactation consultant and writer covering maternal/child health, parenting, general health and wellness, and mental health. She has worked with breastfeeding parents for over a decade, and is a mom to two boys.